<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Node类型</title>
</head>
<body>
    <div class="father" id="father">
        <div class="son_1">11111111111111111111111111111111111111111111</div>
        <div class="son_1">2</div>
        <div class="son_1">3</div>
        <div class="son_1">4</div>
    </div>
    <ul id="ul">
        <li>aaa</li>
        <li>bbb</li>
        ccc
      </ul>
</body>
<script>
    window.onload=function(){
        console.log(document.documentElement);
        console.log(typeof(document.documentElement));

        var dfc = document.getElementsByClassName("father");
        console.log(dfc);
        console.log(dfc[0].childNodes);
        console.log(dfc[0].lastChild);
        var df = document.getElementById("father");
        console.log(df);
        console.log(df.childNodes);
        // console.log(document.body.childNodes);
        // var oUl=document.getElementById("ul");
        // console.log(oUl.childNodes);
    }
</script>
</html>